"I don't know," Harden said. "Maybe a new league, seeing some new guys and they really haven't seen me that much. And you have to give a lot of credit to [ Geovany] Soto too. He really has a good idea of what he's doing back there, and every game we've worked we've been on the same page."

Since throwing 51/3 shutout innings in his debut July 12, Harden has given up one or fewer runs in six of his seven starts.

He lowered his earned-run average as a Cub to 1.50 Tuesday as the Cubs posted their sixth shutout.

Harden and Johnny Cueto engaged in an interesting pitching duel for most of the night before the Cubs offense finally broke through in the fifth after shooting itself in the foot early on, stranding runners in scoring position in the second, third and fourth innings.

Soto's base-running proved to be as valuable as his pitch-calling. He began the fifth with a line shot to right-center field that deflected off the wrist of a diving Corey Patterson. Soto scooted to third with his second triple of the year.

Cueto pointed to third, where no one was covering the bag, so Soto had ample room to maneuver.

As soon as Encarnacion rifled the throw to first, Soto took off and scored on a wide throw from first baseman Joey Votto, with Fukudome taking third.

"I just followed the third baseman down the line," Soto said. "I was pretty far down, and whenever he let go of the ball … I thought it was going to be close.

"I'm not that fast. I went headfirst into home plate."

Piniella lauded Soto for his heads-up base-running.

"That's exactly the way you do that play, and you don't expect it with a catcher," he said. "Just good base-running, good heads-up baseball."

Harden retired the first 10 batters he faced before Jeff Keppinger's one-out single in the fourth. After walking five men last week against Atlanta, Harden command was impeccable. Since joining the Cubs, he has struck out 59 against 14 walks.

The Cubs added four runs in the eighth off the Reds bullpen.

Alfonso Soriano blew through a stop sign to score from second on Derrek Lee's single off Mike Lincoln, and Aramis Ramirez followed with an RBI double to make it 3-0. Fukudome's two-run single after an intentional walk to Soto made it 5-0, and the Reds were finished.

The Cubs are 19-6 since Alfonso Soriano's return, but the left fielder said it's just a coincidence.

"This game is not like basketball, where one player can make a difference," Soriano said. "I add a lot of motivation, and as a team we play better, but we have a lot of great hitters. One day it's Aramis [Ramirez], one day it's Derrek Lee, one day it's Soto, and one day [Mark] DeRosa. It's not just one guy."